The Quartz II features Super MSB Technology which is a ring shaped protection at the base of the helmet that reinforces the perimeter for enhanced protection. It also has a lightweight composite skeleton that provides structural support and integrity on impact. Included in the box is the Spiderlock Vision Light that adapts to the Spiderlock Retention System for improved visibility and safety. Sizes:S: 612 7, 2012 22 in, 52 56 cmM: 7 738, 22 2314 in, 56 59 cmL: 738 734, 2314 2412 in, 59 62 cmXL: 734 8, 2412 2534 in, 62 65 cm